Styrene butadiene rubber (SBR) friction materials containing different carbon fiber (CF) content were prepared using molding process. The effects of CF content on mechanical property, friction performance and wear rate were studied. Worn surfaces of samples were analyzed by scanning electron microscope. The results show that with increasing fiber content, the tensile strength decreases first and then presents an increment trend. Both the friction coefficient and wear increased with load, and the low molecular weight polybutadiene liquid rubber graft maleic anhydride (LMPB-g-MAH)-treated fiber shows lower friction coefficient and wear. LMPB-g-MAH-treated CF/SBR composite was used for some components or parts of machines in chemical engineering, textile engineering, food processing, paper making industry, pharmacy, transportation engineering, agricultural engineering as well as coal and ceramic production.